I have a mid eighties Peugeot that has been serving me very well after my recent purchase and a few repairs (Thanks again Jim).
The only problem is I live in a pretty hilly area and the gearing on this bike is much higher than I think would be ideal. (I can keep pace with my carbon riding buddies except up bigger hills) What is the best route to change this?
The cassette does not look like it comes off with a "normal" cassette tool like I have played with on my MTB and I am wondering if I need to buy a whole new rim or should I look for a different crank?

Basically, it's not a cassette. It's a freewheel. On your MTB, the freewheeling mechanism is built into the hub, but on older bikes, it's built into the cogs assembly, which screws onto the hub. You'll need the appropriate freewheel remover, a vice, and perhaps a chainwhip. Replacement freewheels are pretty cheap, and I certainly wouldn't switch out the wheel unless there was another reason. I can't think of any reason why you'd want to change the cranks.

Go here for more details:

https://www.sheldonbrown.com/free-k7.html

Your bike most likely has a freewheel instead of a cassette. You can read about the difference here: https://www.sheldonbrown.com/free-k7.html.

They can be changed, but it requires a special tool or taking it to the shop. Depending on your crank set (does it have 5 allen bolts?) and availability of used parts, it can be much easier/cheaper to put on a chain ring that is a tooth or two smaller.

A couple other options are to get faster or find slower friends

10 to 1, being a Mid 80's Peugeot, It's probably Helicomatic. In which case, you won't be finding a new freewheel that fits.

Forgive me, I was refering to changing the chain ring, not entire crank. It appears to be mounted with five allen heads, so can I likely just replace the small ring to lower the gearing? Would I likely need to replace the derailleur as well?

+1 -1

I agree that its Helicomatic. Essentially its a 'freewheel' that slides onto the hub with splines but its secured with a lockring.

Check the usual sources.....you may not find the gears your looking for right away but you will find them.

Is the chain ring likely to be compatible with modern pieces?

That all depends on your bolt circle diameter -- start with the SheldonBrown.com glossary definition for BCD. If you have a modern road standard double with a 130mm BCD, you can go as low as 38 teeth, which you should have no trouble finding. With a 110mm BCD, which was typically used on mountain bikes of your era, you can drop to 34 teeth, or to 24 if you have a triple with a smaller granny bolt circle.

If either of your derailleurs cannot handle the increased difference in chainring size, consider replacing both chainrings with smaller ones. On Capo #1, instead of a typical ca. 1980 52-42 combo, I use 47-38, which lowers all gear ratios by 10% for a given cogset.

Yes, absolutely. You need to measure the BCD, or Bolt Circle Diameter (ie the diameter of the circle of allen key bolts). There are various BCD standards, but you'll absolutely be able to find a replacement. Your freewheel might be a helicomatic, but it also might not. I wouldn't take that as quite such a given as people are suggesting.

What crank set is on there now?

My parts bin has been greatly reduced, but I have a 40t 130bcd Sugino chain ring you are more than welcome to if it will work for you. I'll even ride up to deliver it (any excuse to get on the NCR trail )

It's a Stronglight Crank with I think a 7 cm bolt spacing (no metric measureing tape 2.75")

122 38 71.7 Stronglight 93, others (Obsolete)

I'm guessing this would be it BCD=122. Not 100% though.

You gotta love the French.

I find used, complete vintage wheel assemblies on Craigslist for pretty low prices. A front and rear Araya rim'ed, alloy 27" set cost $10. It included a SunTour 14-30 freewheel.